Magnon spectroscopy in the electron microscope.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40702193.
- Also identified by DOI 10.1038/s41586-025-09318-y and PMC identifier 12328233.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The miniaturization of transistors is approaching its limits owing to challenges in heat management and information transfer speed<sup>1</sup>. To overcome these obstacles, emerging technologies such as spintronics<sup>2</sup> are being developed, which make use of the electron's spin as well as its charge. Local phenomena at interfaces or structural defects will greatly influence the efficiency of spin-based devices, making the ability to study spin-wave propagation at the nanoscale and atomic scale a key challenge<sup>3,4</sup>. The development of high-spatial-resolution tools to investigate spin waves, also called magnons, at relevant length scales is thus essential to understand how their properties are affected by local features. Here we detect bulk THz magnons at the nanoscale using scanning transmission electron microscopy (STEM). By using high-resolution electron energy-loss spectroscopy with hybrid-pixel electron detectors, we overcome the challenges posed by weak signals to map THz magnon excitations in a thin NiO nanocrystal. Advanced inelastic electron scattering simulations corroborate our findings. These results open new avenues for detecting magnons and exploring their dispersions and their modifications arising from nanoscale structural or chemical defects. This marks a milestone in magnonics and presents exciting opportunities for the development of spintronic devices.